Feed-Forward XOR PUF Security Against Linear Modeling
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Solution Overview
Problem
Strong Physical Unclonable Functions (PUFs) face issues of low reliability and vulnerability to attacks due to their susceptibility to linear modeling, which allows attackers to clone them easily.
Innovation Solution
The implementation of multiple feed-forward PUFs with an exclusive-or (XOR) circuit to produce a single XOR response, enhancing uniqueness and security by introducing non-linearity and alleviating bias in component PUFs, resulting in a more secure and reliable PUF design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard PUFs are used, then implementation is simple, but they are vulnerable to linear modeling attacks and cloning
Solution Approach 1:
The patent combines multiple PUF instances with different bias characteristics to create a composite PUF system. By XORing responses from multiple PUFs with opposing biases, the system achieves both security against linear modeling attacks and resistance to cloning, while maintaining relative implementation simplicity through modular architecture
Solution Approach 2:
The patent changes the bias parameter of PUFs by applying inverse challenges to flip responses. This parameter transformation allows the system to generate PUFs with opposite biases, which are then combined to create a secure composite PUF that resists linear modeling attacks while maintaining implementation feasibility
2Reliability
If multiple PUFs with opposite biases are combined using XOR, then security against linear modeling attacks improves, but device complexity increases
Solution Approach 1:
The patent segments the PUF system into multiple independent instances, each with distinct bias characteristics. By dividing the security function across multiple segments and combining them through XOR operations, the system achieves superior resistance to linear modeling attacks while managing complexity through modular design
Solution Approach 2:
The patent creates a universal PUF construction that can generate PUFs with any desired bias by selecting appropriate component PUFs and challenge configurations. This multi-functional approach allows the same architecture to produce PUFs with opposite biases, reducing the need for separate hardware designs and managing overall system complexity
3Reliability
If PUF responses are XORed together, then uniqueness and security improve, but reliability under environmental variations deteriorates
Solution Approach 1:
The patent uses PUFs with opposite biases as counterweights to each other. When XORed together, the opposing biases cancel out environmental variations and systematic errors, resulting in a composite PUF response that maintains both high uniqueness and improved stability under environmental conditions
Solution Approach 2:
The patent deliberately introduces asymmetry by using PUFs with opposite biases rather than identical PUFs. This asymmetric configuration ensures that environmental variations affect each PUF differently, and the XOR operation cancels out these asymmetric effects, improving response consistency while maintaining security
Data Source
AI summary
An apparatus includes a first feed-forward PUF, a second feed-forward PUF and an exclusive-or circuit configured to perform an exclusive-or operation of an output of the first feed-forward PUF and an output of the second feed-forward PUF.